<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="first.css">
    <link rel="stylesheet" href="second.css">
    <style>
        body {
            background: #fcf5bf;
        }
        @media screen and (min-width: 850px) {
            body {
                color: #0a050a;
                font-size: 50px;
            }
            div {
                float: left;
                box-sizing: border-box;
            }
            #first {
                width: 60%;
            }
            #second {
                width: 40%;

            }
        }
        @media screen and (max-width: 850px) {
            body {
                color: #ff1000;
                font-size: 40px;
            }
        }
        @media screen and (max-width: 800px) {
            body {
                color: #09ff19;
                font-size: 35px;
            }
        }
        @media screen and (max-width: 700px) {
            body {
                color: #1903ff;
                font-size: 30px;
            }
        }
        @media screen and (max-width: 600px) {
            body {
                color: #ffafc2;
                font-size: 25px;
            }
        }
        @media screen and (max-width: 500px) {
            body {
                color: #fff600;
                font-size: 20px;
            }
        }
        @media screen and (max-width: 400px) {
            body {
                color: #62d6ff;
                font-size: 16px;
            }
        }
        @media screen and (max-width: 300px) {
            body {
                color: #ab1eff;
                font-size: 14px;
            }
        }
        @media screen and (max-width: 200px) {
            body {
                color: #84d8ff;
                font-size: 10px;
            }
        }

    </style>
</head>
<body>
<div id="first">哈哈哈哈</div>
<div id="second">嘿嘿嘿嘿</div>
<script src="first.js" type="text/javascript"></script>
<script src="second.js" type="text/javascript"></script>
</body>
</html>